Changelog

The catalog just grew by 217 puzzles to 241, and with it two disciplines graduate into full tracks alongside Algorithms, Database / EF, and Architecture:

🧹 Refactoring (39 puzzles): inherit working-but-awful code — including the famous Gilded Rose — and clean it up. The tests must stay green while structural gates measured from your source (method length, cyclomatic complexity, nesting depth, duplicate blocks) force the mess out.

🛡️ Secure Coding (32 puzzles): fix functionally-correct-but-exploitable code against real attack payloads — path traversal, Zip Slip, ReDoS, log forging, injection. Two suites grade every submission: exploits blocked and behavior preserved.

The existing tracks grew too: 123 algorithm puzzles with performance gates and allocation budgets, 25 architecture katas, and 22 database puzzles — including the new plan-graded puzzles where the execution plan itself is pass/fail.

Database puzzles now grade how the database executed your query, not just what it returned. Submit a LINQ solution and the results panel shows what the database actually did — and puzzles can grade that execution. Getting the right rows the wrong way is now a visible, gradeable mistake.

Time wasn’t the whole story, so now it isn’t the whole grade: every test reports bytes allocated on the managed heap, and puzzles can set an allocation budget alongside the time budget. The results panel got a memory-budget bar to match — fast but wasteful no longer passes quietly.

The whole front end was rebuilt in React — same dark, keyboard-friendly workspace, now fully responsive down to mobile with a slide-over puzzle drawer and Problem / Code / Results tabs. Monaco (the editor inside VS Code) is bundled locally, your in-progress code and solved puzzles carry over, and everything renders noticeably faster.